Nielsen: Android gains, iPhone slips

In a new survey of prospective U.S. buyers, RIM and Microsoft drift, Nokia disappears

The launch of the Verizon (VZ) iPhone has not visibly slowed the triumphant march of Google’s (GOOG) Android operating system through the mobile heartland of America, according to a Nielsen Wire report released Tuesday.

In monthly surveys conducted from January to March 2011 — on either side of the Feb. 10 Verizon launch — 31% of U.S. respondents planning to buy a new smartphone in the next year said they wanted an Android, up from 26% six months earlier.

Only 30% said they wanted an iPhone, down from 33%. Research in Motion (RIMM), Microsoft (MSFT), Palm (HPQ) and Other also lost ground. Americans who plan to buy Nokia (NOK) smartphones were lost in the round-off error.

If there is any comfort for Apple (AAPL) in the results it is that Not Sure grew to 20% from 18%. That and the fact that Apple sold $10.45 billion worth of iPhones last quarter, overtaking Nokia — the world’s largest manufacturer of mobile phones — for the first time.

It’s not clear how much additional ad revenue Android generates for Google, but it couldn’t be that much.

Below: Nielsen’s pie charts of market share of recent buyers and total installed base.